text: # Copyright (c) Microsoft Corporation. All rights reserved.
  # Licensed under the MIT License.
  
  """Base classes for all Policy estimators."""
  
  import abc
  import numpy as np
  
  
  class PolicyLearner(metaclass=abc.ABCMeta):
  
      def fit(self, Y, T, *, X=None, **kwargs):
          pass
  
      def predict_value(self, X):
          pass
  
      def predict(self, X):
          pass
  